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    <title>Document</title>
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<script>
    class Ani {
        constructor(f){
            this.foot = f;
            this.type = '猫科动物';
        }
    }

    class Tighr extends Ani {
        // this 指向当前对象
        // super指向父类对象 只能写函数里面
        constructor(){
            super(4);
            this.name = '老虎';
            this.adress = '笼子';
        }
    }
    let tiger = new Tighr();
    console.log(tiger);
</script>